Just picked one up as could be useful for anything. Its fairly small and compact, usually used for camping, fishing, gigs etc. (see pic)
Comes with a nice little carry case. Im leaving in my car as it folds away nicely and I can use it when im doing DIY and painting (can set up my the seat and sit anywhere lol).
Was in my local store, near the camping, airbeds stuff --> £1.50 so worth a punt, would imagine its nationwide.
BTW John Lewis do the same for nearly £6http://www.johnlewis.com/230856075/Product.aspx?source=14798
UPDATE - some ASDAs 75p :)